Rotary waveguide joints having a liquid transport system

ABSTRACT

The invention relates to a rotary waveguide joint comprising a coaxial line having an outer conductor divided into a fixed lower part and an upper part which is rotatable with respect to said lower part which is rotatable with respect to said lower part about a fixed hollow inner conductor, a choke-coupler and two rectangular waveguides, which are connected to the end portion of said upper and lower part respectively in a direction at right angles to said coaxial line. The inner conductor contains a tube through which a cooling liquid is forced upwards, while the cooling liquid is carried off downwards through the space between the inner conductor and said tube. Said cooling liquid is conveyed to a heat exchanger located on a rotating platform.

United States Patent 1 13,599,127

(72] Inventor Jflw ls Willem Hendrik Krug 2,853,681 9/1958 Smoll .1 333/98 (R) X Borne, Netherlands 2,884,603 4/ l 959 Bird et al. 1 333/22 F pp 807326 2.994.338 8/[961 Wilson 1. 137/340 l Filed M r-1 ,1969 3 lO6,600 l/l963 Cr0sby..... v H 174 151C) 5] Patented g- 3,478,282 11/1969 Smith .2 3.11/21 [7 Assignee N.V. IIOIIRIldSQ Signaalapparaten (32] Priority mfg: $3 Nmmmds 1,1 81,935 6/1959 France 333/22 (F) Neherlands 774,204 5/1957 Great Britain l 74/15 (C) [3 [1 6803914 Primary xaminerHerman Karl Saalbach Assistant Examiner-Wm. H1 Punter Attorney- Frank R Trifari [54] ROTARY WAVEGUIDE JOINTS HAVING A LIQUID TRANSPORT SYSTEM 5 Claims, 2 Drawing Figs.

ABSTRACT: The invention relates to a rotary waveguide jOlllI [52] U5. CI 333/98 TN, comprising a coaxial line having an outer Conductor divided 333/22 174/15 C into a fixed lower part and an upper part which is rotatable [5 l] Int. Cl Ilolp 1/06, with respec to id lower part which is rotatable with respect HOIP 7/34 to said lower part about a fixed hollow inner conductor, a Field of Search 333/98 R,

choke-coupler and two rectangular waveguides, which are 22 R98; 174/15 C; 137/340 connected to the end portion of said upper and lower part respectively in a direction at right angles to said coaxial line.

Reerences Cited The inner conductor contains a tube through which a cooling UNITED STATES PATENTS liquid is forced upwards, while the cooling liquid is carried off 2,031,975 2/1936 Northrup ..l74/l5 (C) UX downwards through the space between the inner conductor 2, /1 2 i l ll 333/98 (R) and said tube. Said cooling liquid is conveyed to a heat 2,802,986 8/1957 Chase et al. 333/22 (F) UX exchanger located on a rotating platform.

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ROTARY WAVEGUIDE JOINTS HAVING A LIQUID TRANSPORT SYSTEM The invention relates to rotary waveguide joints of the type comprising a coaxial line having an outer conductor divided into a fixed lower part and an upper part which is rotatable with respect to said lower part about a hollow inner conductor rigidly connected in said lower part, a choke coupler for coupling the two parts to one another, and two rectangular waveguides provided with impedance transformers connecting said waveguides to the end portion of said upper and lower part respectively in a direction at right angles to said coaxial line.

Such rotary waveguide joints are known and find wide application in radar apparatus having an antenna system arranged on a rotating platform. This rotating platform may also carry elements, for example, high frequency filters, which must be cooled. This is usually effected by means of a heat exchanger which dissipates its heat to the ambient atmosphere, possibly in a forced manner. If, however, high powers are used, such an air cooling system proves to be insufficient, unless a very bulky heat exchanger can be mounted on the rotating platform. This obviously gives rise to great difficulty in view of the dimensions, the weight and the space available on the platform.

It is an object of the present invention to eliminate this difficulty.

For this purpose, the rotarywaveguide joint of the invention is provided with an inner conductor, containing a tube through which a cooling liquid is forced upwards, said cooling liquid being carried off downwards through the space between the inner conductor and the tube, provision further being made of means connecting the rotating part of the outer conductor to a heat exchanger on a rotating platform for feeding the cooling liquid to and from said heat exchanger. These steps are based on the recognition that the cooling may be effec'ted by a system feeding cooling liquid by way of said rotary waveguide joint to and from the elements to be cooled on the rotating platform. The invention and its advantages will be elucidated by the following description of an embodiment thereof, given by way of example only, with reference to the accompanying drawings, in which:

FIG. Us a schematic diagramof the rotary waveguide joint in accordance with the invention, and

FIG. 2 is a longitudinal sectional view of part'of this rotary waveguide joint.

Like reference numerals denote like parts in both figures.

FIG. 1 reference numeral 1 designates the outer conductor of a coaxial line. This outer conductor is divided into a fixed lower part and an upper part which is rotatable with respect to the lower part about a hollow inner conductor 2. The latter is rigidly secured to the lower part of outer conductor 1. The two parts of outer conductor 1 are coupled to one another by means of a choke coupler 3. The arrangement further comprises two rectangular waveguides 4 and 5 provided with impedance transformers 6 and 7 connecting said waveguides to the end portion of said upper and lower part respectively, in a direction at right angles to said coaxial line. The upper part of outer conductor 1 is closed by means of an end cap 8. In order that the upper part of outer conductor 1 may easily rotate about inner conductor 2, choke coupler 3 and end cap 8 are provided with ball bearingstnot shown).

The inner conductor 2 of the rotary waveguide joint according to the invention contains a tube 9 through which a cooling liquid is forced upwards, this cooling liquid being carried off downwards through the space between the inner conductor 2 and the tube 9, provision being further made of means 10 connecting the rotating part of the outer conductor 1 to a heat exchanger 11 on a rotating platform for feeding said cooling liquid to and from said heat exchanger.

The latter means 10 are shown in FIG. 2. They comprise a cylindrical casing 17 which by way of the end cap 8 is fixedly connected to the upper, rotary part of the outer conductor 1, a

tube 12, a ball bearing 23 enabling the casing 17 to rotate about the length of tubing 12, and sealing rings 18-22. Cylindrical casing 17 has an outlet pipe 15 and an inlet pipe 16 which are to be connected to the heat exchanger 11. Part of tube 12 has an inner diameter such that it tightly fits around the hollow inner conductor 2 projecting from end cap 8, the inner diameter of the remaining part being so much smaller that it is a continuationof said hollow inner conductor. ln order to prevent tube 12 from rotating about inner conductor 2 a key (not shown) is provided extending in its direction of length.

The part of tube 9 projecting from the inner conductor 2 opens into a chamber 13 and the continuation of the inner conductor 2 opens into another chamber 14. The cooling liquid forced up through tube 9 is fed by way of chamber 13 and outlet pipe 15 to heat exchanger 11. The cooling liquid, the temperature of which has been raised by the heat exchange, is carried off through inlet pipe 16, chamber 14 and the space between the inner conductor 2 and the tube 9. The path taken by the liquid is shown by arrows in both figures.

Because of the prevailing pressures in chambers 13 and 14 and because the liquid in one chamber must not be mixed with that in the other chamber, casing 17 must tightly fit around tube 9. This is effected by the sealing rings 18 and 19. Owing to the rotation of casing 17 the sealing rings 18 and 19 and/or the tube part in contact with the sealing rings 18 and 19 will be worn, the wear showing itself as a change in pressure difference between chambers 13 and 14. The sealing rings and/or the tube 9 must then be replaced. To prevent the liquid contained in chamber 14 from penetrating into a space 24 in which the ball bearing 23 is arranged, casing 17 must also tightly fit around tube 12. This is effected by means of the sealing rings 20 and 21. The sealing rings 20 and 21 and/or the tube part in contact with the sealing rings 20 and 21 will be worn by the rotation of casing 17 and the liquid will trickle from chamber 14 into the space in casing 17 between sealing rings 20 and 22. It is possible to check the separation by making a duct 25 in the casing. The sealing rings 20 and 21 and/or tube 12 must then be replaced. A further sealing ring 22 is provided to prevent the ambient atmosphere penetrating space 24 in which ball bearing 23 is arranged.

Finally, it should be noted that tube 12 though advantageous is not essential. If tube 12 is omitted, casing 17 must rotate directly about the inner conductor 2 by means of ball bearing 23 and sealings rings 20, 21 and 22 must tightly fit around inner conductor 2. After some time the sealing rings and/or the inner conductor in contact with the sealing rings will be worn, necessitating the inner conductor of the rotary joint to be replaced. This is an expensive and time-consuming operation, since the rotary joint will have to be disassembled, repaired and readjusted. The radar apparatus cannot be used during this repair. Replacement of tube 12 does not give rise to this difficulty. Even if the cooling system is out of use the radar apparatus may be operative, although with reduced power.

lclaim:

1. A rotary waveguide joint comprising, a coaxial line having an outer conductor divided into a fixed lower part, a rotatable upper part and a hollow inner conductor rigidly connected to said lower part, said upper part being rotatable with respect to said lower part about said hollow inner conductor, a choke coupler for coupling said upper and lower parts to one another, two rectangular waveguides having impedance transformer connecting said waveguides to end portions of said upper and lower parts in a direction orthogonal to said coaxial line, a first tube centrally positioned within said inner conductor for supplying a cooling liquid from said fixed lower part to said rotatable upper part, said cooling liquid being returned from said rotatable upper part to said fixed lower part through space between said inner conductor and said first tube, an end cap having said inner conductor and said first tube projecting therefrom to close said rotatable upper part, a cylindrical casing fixedly connected to said upper part by means of said end cap for connecting said rotatable upper part to a heat exchanger on a rotatable platform for feeding said cooling liquid to and from said heat exchanger, and a second tube located within said casing and having a part with an inner diameter such that it tightly fits around said hollow inner conductor for sealing said cooling liquid within said casing and a part with an inner diameter smaller than said part around said inner conductor so that it is a continuation of said inner conductor for returning said cooling liquid.

2'. A rotary waveguide joint as claimed in claim 1, said cylindrical casing comprises a ball bearing for rotation about said second tube.

3. A rotary waveguide joint as claimed in claim 1 wherein said cylindrical casing comprises an inlet pipe, an outlet pipe, a first chamber into which a section of said first tube projecting from the inner conductor opens and a second chamber through which said first tube passes and into which said continuation of said inner conductor opens, said outlet pipe and said inlet pipe being connected to said first and second chambers respectively.

4. A rotary waveguide joint as claimed in claim 3 wherein said first and second chambers are separated from one another and from a space housing ball bearings by means of sealing rings. I

5. A rotary waveguide joint as claimed in claim 4 wherein said cylindrical casing comprises an opening communicating with the ambient atmosphere, said opening providing a means to check separation between said second chamber and said space housing said ball bearings. 

1. A rotary waveguide joint comprising, a coaxial line having an outer conductor divided into a fixed lower part, a rotatable upper part and a hollow inner conductor rigidly connected to said lower part, said upper part being rotatable with respect to said lower part about said hollow inner conductor, a choke coupler for coupling said upper and lower parts to one another, two rectangular waveguides having impedance transformer connecting said waveguides to end portions of said upper and lower parts in a direction orthogonal to said coaxial line, a first tube centrally positioned within said inner conductor for supplying a cooling liquid from said fixed lower part to said rotatable upper part, said cooling liquid being returned from said rotatable upper part to said fixed lower part through space between said inner conductor and said first tube, an end cap having said inner conductor and said first tube projecting therefrom to close said rotatable upper part, a cylindrical casing fixedly connected to said upper part by means of said end cap for connecting said rotatable upper part to a heat exchanger on a rotatable platform for feeding said cooling liquid to and from said heat exchanger, and a second tube located within said casing and having a part with an inner diameter such that it tightly fits around said hollow inner conductor for sealing said cooling liquid within said casing and a part with an inner diameter smaller than said part around said inner conductor so that it is a continuation of said inner conductor for returning said cooling liquid.
 2. A rotary waveguide joint as claimed in claim 1, said cylindrical casing comprises a ball bearing for rotation about said second tube.
 3. A rotary waveguide joint as claimed in claim 1 wherein said cylindrical casing comprises an inlet pipe, an outlet pipe, a first chamber into which a section of said first tube projecting from the inner conductor opens and a second chamber through which said first tube passes and into which said continuation of said inner conductor opens, said outlet pipe and said inlet pipe being connected to said first and second chambers respectively.
 4. A rotary waveguide joint as claimed in claim 3 wherein said first and second chambers are separated from one another and from a space housing ball bearings by means of sealing rings.
 5. A rotary waveguide joint as claimed in claim 4 wherein said cylindrical casing comprises an opening communicating with the ambient atmosphere, said opening providing a means to check separation between said second chamber and said space housing said ball bearings. 